The present invention relates generally to crash detection systems for automotive vehicles, and more particularly to a pre-crash threat assessment system for a crash detection system.
Due to the current density of traffic on the roads, motor vehicle operators are flooded with information. Consequently, operating a motor vehicle is a complex procedure in which various situations arise where the operator has limited, little, or no time to react or to manually engage safety measures.
Many previously known crash detection systems have incorporated crash detection algorithms based on sensed data. The application of remote sensing systems using radar, lidar, and vision based technologies for object detection, tracking, alarm processing, and potential safety countermeasure activation is well known in the art.
Based on range and bearing information provided by radar, lidar or vision based sensing systems and additional information obtained from the host vehicle sensors, various algorithms have been used to track the paths of host and target vehicles. Algorithms have also been incorporated to estimate the future position of obstacles or vehicles in the host vehicle path.
Safety systems, such as airbags and safety belt pretensioners, activate after physical contact occurs between two vehicles. A typical accident occurs within 90 ms, whereas a typical airbag deploys within approximately 70 ms. A typical motorized belt pretensioner requires about 200 ms to reduce the slack in the belt system. Through accident prediction, safety system activation timing is potentially improved.
Currently, accident prediction algorithms are employed primarily for accident warning and avoidance and therefore typically cover ranges up to a few hundred meters ahead of the host vehicle. However, in unavoidable collision situations, the range under consideration is substantially short. Therefore, damage minimization techniques must predict an unavoidable collision and deploy safety measures within a short time.
The limitations associated with current accident damage minimization techniques have made it apparent that a new technique to minimize collision damage is needed. The new technique should predict a target vehicle position with respect to a host vehicle and should also substantially minimize the time between an anticipated unavoidable collision detection and subsequent activation of safety devices. The present invention is directed to these ends.
The present invention provides a remote, non-contact sensing based pre-crash threat assessment system using a generalized conic target path prediction methodology. The present invention also provides a non-contact sensor-based pre-crash threat assessment system for an automobile.
In accordance with the present invention, a pre-crash assessment system, which includes a host vehicle in motion, is disclosed. A remote sensor (or sensing system), that detects first, target object dynamics, is coupled to the host object. Status monitoring sensors which detect host object dynamics are also coupled to the host object. A first safety device actuator, also coupled to the host object, activates a first safety device when a potential for crash is established such that a crash between the host object and the first target object is unavoidable. A first threshold for the first safety device actuator is defined by first safety device actuation criteria.
A safety device controller, which is coupled to the host object, generates tracking signals based on the host object dynamics and the first target object dynamics. The controller also estimates future positions of the host object and the first target object. Representation of the target trajectory is in the form of a generalized conic curve which accounts for possible straight and curved path trajectories. The controller further estimates whether the potential for crash between the host object and the first target object is within the first threshold for the first safety device actuator. The potential for impact is determined by computing intercept coordinates and intercept time intervals on the basis of the predicted target and host vehicle paths. Potential lateral and longitudinal intercept points are computed to determine the potential for impact. The safety device controller further controls the first safety device actuator based on the first threshold criteria and other safety device specific actuation criteria.
Advantages of the current invention are that remote sensing position and bearing information of a target object in the near vicinity of the host vehicle are used and threat assessment is made through a fast, robust and reliable algorithm. Fast algorithms allow more decision making time on the part of vehicle controllers and more deployment time for safety devices and are therefore preferable.
Additional advantages and features of the present invention will become apparent from the description that follows and may be realized by the instrumentalities and combinations particularly pointed out in the appended claims, taken in conjunction with the accompanying drawings.